The invention is particularly intended for use in a missile, whose guidance system of which comprises guidance channels for guidance of the vehicle vertically and horizontally (tipping and yawing, respectively). A vertical or horizontal error position signal is converted into an elevator or side rudder command, respectively, and provided to the control surface servos of the vehicle.
When guiding a flying vehicle, for instance a missile, it is known to guide the missile vertically and horizontally by means of an error position signal, from for instance a computer. The signal is being converted into a control surface command to the control surface servos of the missile. In order to reduce the tracking error of the system, various circuits are then provided in the guidance system to compensate for various sources of disturbances that influence the missile, and for increasing the stability. One of the properties of the missile at tipping and yawing oscillations is that it normally has low damping, and this must usually be increased by synthetic means if the missile is to be guided. The conventional method of increasing this damping is to measure the angular velocity or the transversal accelerations of the vehicle, and from these values calculate a control surface contribution that has a damping effect on the vehicle (active method).
With this technique the band width of the control surface servos must be substantially higher than the natural frequency of the missile; which in certain applications can give unnecessarily high power requirements. It can, for instance, be necessary to use hydraulic motors instead of electric motors, resulting in a higher weight, price and complexity, even for small missiles.